This invention relates to feedthrough devices for supply lines, the term "supply line" as used herein covering any utility carrier, for example a cable, a wire, or a pipe, which must be passed through an aperture in a wall member, for example a bulkhead, the casing of a machine, or a housing for electrical apparatus.
When such supply lines, especially flexible supply lines, are fed through an aperture it is first of all important that there is no danger of rupture of the supply line caused by the rough edges of the aperture. It is also generally necessary that the supply line should be firmly held in relation to the aperture to avoid unwanted movement of the supply line both within the aperture and on either side of it. Finally, in many applications it is desirable to employ an airtight and watertight enclosure for housing junctions and other installations to prevent damage, corrosion or shorting of the conductors therein. One conventional practice to achieve such enclosure has been the use of an insulated stuffing box. However, stuffing boxes are cumbersome and difficult to adjust and a large number of separate components are required to produce the desired tight fit. More recently, grommets formed from heat recoverable materials have been suggested in British Pat. Nos. 1,167,587, 1,238,144 and 1,294,510. However, the grommets of those patents suffer from the disadvantage that they require access to both sides of the wall member in order to effect installation thereof.
In U.S. Pat. No. 3,548,079 there is described a bulkhead feedthrough device having two members, the first of which has a heat recoverable portion and the second of which performs a wedging function. In this device, the first member is positioned such that it surrounds the conductor or other substrate and such that a portion thereof extends through an aperture in an enclosure. The first member is provided with an annular sleeve which is positioned radially adjacent to the aperture. The heat recoverable portion is then caused to recover around the substrate and the second member is inserted within the annular sleeve to force the sleeve radially outward into contact with the walls of the aperture. The construction of this device is such that installation thereof requires access to only one side of the bulkhead. The feedthrough device of U.S. Pat. No. 3,548,079 has been found to work satisfactorily in many applications, but is not suitable for use where it is required to seal against relatively high pressures.